1. Field of the Invention
The present invention relates to motorcycle trailers. More specifically, it relates to trailers that have an aerodynamically-designed storage compartment, a suspension spring assembly for the hitch and draw bar to reduce the impact on the motorcycle from the trailer's reaction to bumps, and to two-wheel independent suspension where each suspension mount on the trailer is above the axle of each tire. Such mounting of the swing arm reduces vertical acceleration associated with the wheel hitting a bump, resulting in decreased vertical forces on the trailer. In addition to the independent suspension, the suspension spring assembly for the hitch and draw decrease the transfer of vertical force to the motorcycle.
2. Description of the Related Art
There are a large number of motorcycle trailers on the market that try to have improved aerodynamic characteristics. One method to improve aerodynamics changes the shape of the trailer so that the front of the trailer has a somewhat pointed nose. This design causes the air to flow easily underneath or over the top of the trailer. However, the prior art designs typically leave the back end of the trailer square, which does nothing to direct the convergence of air around the back of the trailer. Another method of improving the aerodynamic characteristics of the trailer involves decreasing the size of the trailer such that it is smaller than the motorcycle so that the motorcycle diverts most of the wind. This approach has the obvious drawback of reducing the available cargo room.
While there is prior art using independent suspension systems to make the ride of the trailer smoother over rough roads, these suspension systems typically include swing arms that are below the wheel's axle. When the swing arm is below the wheel's axle, it must rise more steeply when it hits a bump and therefore there is a rougher ride due to higher vertical acceleration. For instance, U.S. Pat. No. 4,536,001 (Wagner) shows a two-wheel independent suspension motorcycle cargo trailer. In this trailer, there is a low center of gravity and an independent suspension system for each wheel instead of a transverse common axle and suspension for both wheels. The low center of gravity and independent suspension were purported to reduce drag and provide a smoother ride. In Wagner, the wheel suspension consists of a swing arm and air shocks to reduce the effects of bumps in the road. However, the swing arm is mounted on the trailer in a location lower than the attachment to the wheel axle.
Finally, the motorcycle trailer currently on the market use a single rigid hitch and drag bar which resists the vertical motion of the motorcycle going over bumps. This mechanism transfers the vertical motion of the trailer to the motorcycle, which makes the motorcycle more difficult to control, reduces the enjoyment of the ride, and increases the fatigue of the rear frame of the motorcycle.